The present invention relates generally to an information processing apparatus, an information processing method, an information decryption apparatus, an information decryption method, an information providing medium, and an information storage medium. More particularly, the present invention relates to an information processing apparatus, an information processing method, an information decryption apparatus, an information decryption method, an information providing medium, and an information storage medium that encrypt information for recording.
Conventional information processing apparatuses for reading and writing information on an information recording medium such as an FD (Floppy Disc), a CD-R (Compact Disc Recordable), a DVD-RAM (Digital Versatile Disc Random Access Memory), or an MD (Mini Disc: trade mark) have no capability of encoding information for recording. Therefore, to encrypt information for recording, information encrypted in advance must be supplied to these information processing apparatuses.
The above-mentioned information encoding is intended to fail attempts of unauthorized duplication or access of information, so that previously encoding information cannot prevent the same from unauthorized duplication. This is because, if an encoding program or a decoding program has been supplied as a program to be executed on a PC (Personal Computer) for example, replicating this program and distributing the replicate program allows unauthorized users to replicate encrypted information as it is and decrypt the replicated information by use of the distributed program.
If an encoding program or a decoding program is supplied as firmware of information processing apparatuses, the information itself recorded on an information recording medium can be easily replicated and preparing the information processing apparatus in which the firmware is installed allows use of replicated information.
To solve this problem, information may be stored in a special memory, for example a semiconductor memory with its reading sequence or the like kept confidential. Unless the reading sequence is known, no information can be read from such a memory.
However, use of the above-mentioned special semiconductor memory requires a predetermined circuit for handing the reading sequence. This makes such a semiconductor memory less general-purpose, increasing its fabrication cost.